What is Emacs ?

Emacs is the extensible,
customizable, self-documenting real-time display editor. This
Editor is used to do a lot of things, from IRC to reading mails
and news, along with "basic" editing, advanced macro, remote
control, multimedia player, and so on..

This webpage is about EMMS, an Emacs "package" that you use
to extend Emacs features to multimedia.